Machine tool controller



April 1947. w. E. ADDICKS ET AL 2,418,149

- I MACHINE TOOL CONTROLLER 2 Sheets-Sheet 1 Filed Feb. 26, 1944 wnaxw W Patented Apr. 1, 1947 MACHINE TOOL CONTROLLER Walter E. Addicks, I1'-vington, N. Y., and Robert O.

Perrine, Wauwatosa, Wis., assignors to Cutler- Hammer, Inc., Milwaukee, Wis., a corporation of Delaware Application February 26, 1944, Serial No. 524,056

7 Claims. 1 This invention relate to machine tool controllers, and while not limited thereto is particularly applicable to controllers for machines such as in ternal thread grinders.

2 I is returned to starting position. It is the usual practice to provide the grinding machine with a mechanism which acts automatically to maintain wheel 2 out of engagement with blank 5 In operating an internal thread grinding madurin 'return movement of head stock I tostartchine it is necessary to efiect grinding and wheel 'ing position. truing operations in a definite sequence detera The sp dle 6 of r d n WheelZ is j'ournale mined by the character of the work being mawithin a pivoted supp t 8 w c is a l by a chined, and the present invention has among its fluid pressure pe at d p n 9 to sw sa d objects to provide a program controller for auto- 10 d n W el in pp c o s etwee a matically effecting such operations in any desired o al p s n illustrated y full lines and t sequence, grinding position illustrated by dotted lines. Pis- Another object is to provide a unita c ntrolton 9 is movable within a stationary cylinder l0 ler or the aforesaid character which is adaptable vi an electroma netic-control valvelll assoto a Wide variety of machining operations, which =ciated therewith which is controlled by a p iro is reliable in operation and which includes a series solenoids SA and SB. Up momentary ener izeof selector switches for programming grinding tion of solenoid SA p sto 9 Operates to move and truing operations of the machine, grinding wheel 2 into its dotted line position for Various other objects and advantages of the -e nd a p a p momentary enerinvention il hereinafter a r, 2 :gization of solenoid SB said piston operates to re- The accompanying drawings illu trat an em turn said grinding wheel to its full line position. bodiment of the invention which will now be de- With g d W eel in i s f l e n01ma1 scribed, it being understood that various modifiposition the p ph ry f i pted to be cations may be made in the embodiment illusillled by e t g m chanism '3. Said truing trated Without departing from the spirit and 1:25 mechanism is p ov ded with the usual diamond scope of th appended 1 m points I2 which are mounted upon a reciprocable In th drawings carriage l3. Carriage I3 is normally in the posi- Figure 1 i a Schematic View m t t tion illustrated by full lines and is 'operatedby a towel thread grinding machine and also certain motor M3 through um of a crank drive elements for conbrolfi g grinding and trujng 13.0 14 to move the diamond DOiIltS l2 into and 0111101 eraticms thereof; and engagement with the periphery of Wheel 2.

Fig. 2 is a diagrammatic view illustrating a pro- Figure 1 s tes a simplified means for congfan'l controller embodying t control ,elements trolling the operation of the driving motors for i11ustratedmFig 1 head stock I, grinding wheel '2 and the truing Referring to Fig. 1, the same schematically ilmechanism AS Show, motors M2 M3 lustrates an internal thread grinding machine e sup l d with current f a 3 p ase s ppl including a head stock l, a circular grinding Circuit indicatedby lines L1, L3 and 11101501 M1 wheei g and Wheel trumg mechanism Head is controlled by a pair of electromagnetic reversstock i carries a rotatable chuck 4 for receiving mg Switches F and R; mam! M2 is controlled a blank 5 to be internally threaded and a motor 40 an magnetic switch G and motor M is 1 is provided for rotating said chuck and for controlled by an electromagnetic switch T. also effecting forward and return movements of purpose hereinafter Set forth head Stock the head stock in timed relation 'to the rotation is provided with limit Switches 2115 of said chuck. Grinding Wheel 2 is fixed to a 3L5; Wheel support 8 is provided with limit rotatable spindle E i drive a motor M2 SWitChES and and Carriage iS provided through the medium of a belt drive 1. During a with limlt 5L3 and Limit Swith grinding operation wheel 2 is heldagainst bodily is proYlded wlth contacts and I'LSb, the movement in aposition illustrated by dotted lines former heme closed a the latter being Open and upon forward movement of headstock I out when head stock 1 m stairtingposition- Limit of a given starting position wheel 2 engages within switch ZLS is provided with vnormally clo d conan opening in blank 5 to internally thread the fleets and no al open contacts ZLS' same. Head stock I is advanced during each which are operated upon movement of headstock revolution of chuck 4 a distance equal to the pitch l into its forward limit. Limit switch 3LS is p of the thread to be ground in blank 5 and upon vided withnormally open contacts which .remain in open position during forward movement of completion of a grinding operation head stock 3 head stock I and are closed momentarily during return movement of the head stock into starting position. Limit switch 4LS is provided with contacts 4LS and lLS which are closed upon movement of wheel 2 into truing position, and limit switch 5LS is provided with normally open contacts 5L8 and 5LS which are closed upon movement of said wheel into grinding position. Limit switch BLS is provided with contacts EiLS and BLS the former being open and the latter being closed when carriage I3 is in normal position, and limit switch 'ILS is provided with normally open contacts TLS and 'ILS and normally closed contacts 'ILS which are operated upon movement of carriage 3 into truing position.

Referring now to Fig. 2, the same illustrates a program controller for controlling switches F, R, 'I', G and Valve solenoids SA and SE to effect grinding and truing operations of the internal thread grinder in a selected sequence. Said controller includes the aforementioned limit switches, a plurality of electromagnetic relays GR, TR, ICR, 20R and 30R, a plurality of manual selector switches S to S and an electromagnetic notching relay NR. Also said controller includes a normally open start cycle push button IS, a normally open wheel start push button H and a normally closed wheel stop push button 58.

As hereinafter set forth, relay GR is responsive to initiate a grinding operation of the machine and relay TR is responsive to initiate a truing operation thereof. Relays GR and TR are controlled by the notching relay NR through the medium of the selector switches S to S As shown, notching relay NR is provided with a rotatable contact arm 0 which is normally held by a spring 20 in the position shown in the drawing to engage a stationary contact 0 and to also maintain an auxiliary switch 2I in open position. Contact arm C is movable out or normal position in a step by step manner to successively engage stationary contacts 0 to c by a ratchetwheel 22 having an operating pawl 23 and a holding .pawl 26 associated therewith. Pawl 23 is operated by a winding 24 and pawl 26 is tripped by a winding 25. Selector switches S to S are respectively connected to contacts 0 to c and each of said selector switches has an intermediate off position and is movable in one direction out of off position to engage a stationary contact a and in the other direction out of off position to engage a stationary contact I).

The function and operation of the aforedescribed controller and also the circuit connections thereof will now be more fully set forth.

Assuming that a work cycle is to be started, switches F, R, G and T are in open position and head stock I, wheel support 8 and carriage 3 of the internal thread grinder are positioned as shown in full lines in Fig. 1. Also the control arm C of notching relay NR is positioned as shown in Fig. 2 to establish circuit from line L through contacts 36R of relay -3CR through contact arm C to stationary contact 0 and through the grind relay operating windin GR to line L Relay GR is thus energized to close its associated contacts GR and GR and to open its associated contacts GR Prior to starting of a work cycle push button I1 is depressed to connect the operating winding G ofswitch G across lines L L through the medium of stop lsh button I-8. Switch G then responds to energize the wheel motor M Switch G is provided with normally open auxiliary'contacts G and upon release of push button I'I said switch is maintained energized through the medium of said auxiliary contacts and stop push button I8.

With wheel motor M in operation, push button I6 is momentarily depressed to effect starting of the work cycle. Upon closure of push button I6 valve solenoid SA is connected across lines L L through the medium of contacts GR of grinding relay GR and piston v9 then operates to move grinding wheel 2 from its full line truing position into the grind position illustrated by dotted lines. Upon movement of wheel 2 into grinding position, limit switch contacts 5L8 close to connect the operating winding F of switch F across lines L L through the medium of limit switch contacts ZLS grind relay contacts GR and normally closed auxiliary contacts R associated with reversing switch R. Switch F then responds and motor M operates to move head stock I forwardly for a grinding operation, Upon forward movement of head stock I out of starting position limit switch ILS operates to open contacts ILS and to close contacts LS and upon completion of the grinding operation limit switch ZLS is operated to open contacts 2L3 and close contact ZLS Opening of limit switch contacts 2LS interrupts the aforedescribed energizing circuit for switch F and upon dropping out of switch F the operating winding R of switch R is connected across lines L L through the medium of limit switch contacts ZLS ILS and auxiliary contacts l associated with switch F. Switch R thus responds to effect operation of motor M in a reverse direction for return of head stock I to starting position. Upon movement of headstock I out of its forward limit, limit switch contacts ZLS are opened but switch R is maintained energized by closure of its auxiliary contacts R Upon return of head stock I into starting position, switch R is deenergized by opening of limit switch contacts ILS to effect stopping of motor M Prior to full return of head stock I to starting contact G into engagement with contact 0 and upon return of head stock I to starting position switch F is again energized through the medium of limit switch contacts ZLS and 5LS grind relay contacts GR and auxiliary contacts R of switch R. Switch F is thus reclosed and the controller will operate as hereinbefore described to move head stock I into its forward limit for grinding operation and then return the same to starting position. During return of head stock I to grinding position, after the aforedescribed second grinding operation, limit switch 3LS again operates to energize winding 24 for movement of contact arm G into engagement with stationary contact 0 However, assuming that switch S is set to engage its associated stationary contact a, grind relay GR will be deenergized when contact arm 0 moves into engagement with contact 0 and truing relay TR will be energized to effect opening of its associated contacts TR and closure of its associated contacts 111 and TR. Upon return of head stock I to starting position valve solenoid :SB will lee-connected across lines L and L through the medium of truing relay contacts TR and limit switch contacts EELS and ILS Upon energization of solenoid, SB valve H is actuated toefiectoperation of piston 9 for movement of wheel 2 irorn its dotted line grinding position into the truing position illustrated by full lines. Upon movement of wheel 2 out of grinding position limit switch 515 opens to interrupt the aforedescribed energizing circuit for valve solenoid SB and upon movement of said wheel into truing position limit switch contacts lLS close to connect the operating winding of relay 10R across the lines L L through the medium of truing relay contacts 1R and limit switch contacts 'lliS Upon response of relay ICR the operating winding T of switch T is connected across lines'L L through the medium of contacts iCR and |CR and switch '1 then responds to effect energization of motor M Carriage 3 is thus operated to move the diamond points i2 into and out of engagement with wheel 2 for truing thereof. Upon movement of carriage l3 out of normal position limit switch contacts EELS close to maintain switch T energized for forward and return movements of carriage l3. Upon movement of carriage 13 into its forward limit, limit switch 'lLS is momentarily operated to interrupt the energizing circuit of relay ICR by opening of contacts lLiS and to establish an energizing circuit for the operating winding 24 of notching relay NR by closure of contacts 'lLS Notching relay NR is thus energized to move contact arm C into engagement with stationary contact Assuming that selector switch S is set to engage its associated stationary contact a truing relay TR is energized upon movement of contact arm G into engagement with contact 0 Relay lCR is thus energized upon return of carriage I3 to normal position through the medium of truing relay contacts TR and limit switch contacts 4LS and iLS to maintain switch T energized for a second truing operation. However, assuming that selector switch S is set to engage its associated stationary contact I) truing relay TR drops out and grind relay GR responds upon movement of contact arm C into engagement with stationary contact 0 Also relay iCR is deenergized by opening of limit switch contacts 7118 and switch '1- is maintained energized by limit switch contacts SLS Upon return of carriage l3 to normal position, limit switch contacts ESLS open and switch T drops out to stop motor M Upon response of grind relay GR, valve operatmg solenoid SA is momentarily energized through the medium of limit switch contacts ILS and grind relay contacts GR and the controller will operate as hereinbefore set fO l'bhlJOQfiiQCl, a grinding operation of the machine.

From the foregoing it is apparent that notching relay NR operates in a step by step manner to effect grinding and truing operations of the machine in a sequence determined by the setting of the several selector switches S. As will now be set forth, the machine is automatically stopped and the controller i automatically reset in normal position upon completion of a selected sequence of grinding and truing operations.

Assuming that one of the selector switches, as for example selector switch S is set to engage its associated contact b for a final grinding operation and that selector switch S is in neutral position. After the final grinding operation head stock I returns to starting position and limit switch 3LS 6 closes to energize operating winding 24 for movement of contact arm C iroin stationary contact 0 i-nto engagement with stationary contact c Grind re'lay GR Sis thus deenergized and upon dropping out thereof the operating winding 2CR of relay 20R is connected across lines L L through the medium :of truing relay contacts TRZ and grind relay contacts (3R Upon return of head stock :I to starting position limit switch contacts L-LS are opened to deenergize switch R for stopping of motor M and limit switch contacts [LS are closed to energize valve operating solenoid SB through the medium of relay 20R and limit switch contacts 5LS Piston'll then operates to move grinding wheel 2 into its tru'ing position .and upon movement of said wheel out of. grinding position limit switch contacts 5L8 are opened to interrupt the energizing circuit for =va'lve operating solenoid 1513. Limit switch contacts iLS close upon movement of grinding wheel .2 into truing position and :an energizing circuit for the operating winding 3CR of relay 36R is thenestablished through the medium of truing relay contacts TRP, grind relay contact GR limit switch contacts (iLS and the auxiliary switch 23f associated with notching relay NR. Relay LSCR responds and in responding the contacts 30R thereof open to 111+ terrupt circuit from line L to contact arm C and the contacts BCR thereof close to establish an energizing circuit for the 'trip coil 25 of notching relay NR. Pawl 26 is thus tripped to permit return of contact arm C to normal position under the action of spring Zil. Upon return of contact armC 'to normal position auxiliary switch 2| is opened to interrupt the energizing circuit for relay 3CR and grind relay GR is energized through the medium ofstati'onary contact 0 of the notching relay. Upon response of grind relay GR contacts GR. are opened to deenergize relay 2GB and contacts GR are closed for a repeat work cycle upon depression of push button [6.

Assuming that selector switch S is set to engage its associated stationary contact a for a final truing operation and that selector switch S is in neutral position. During the final truing operation, limit switch 'ILS is momentarily operated to open its contacts l'LS and to close its contacts .TLS Opening of limit switch contacts 'lLS interrupts the aforedescribed energizing circuit for relay ICE and upon dropping out of said relay switch T is maintained energized by limit switch "contacts BLS pending return of carriage t3 to normal position. Closure of limit switch contacts 'lLS efiects energization of operating winding 24 for movement of contact arm C from stationary contact c into engagement with stationary contact c Truing relay TR is thus deenergized and upon dropping out thereof relay ECR is energized through the medium of contacts TR and GR? Relay 20R then responds but at this time the same does not function since limit switch contacts BLS are in open position. Upon return of carriage l3 to normal position limit switch contacts BLS close to establish the aforedescribed energizing circuit for relay 30R. Trip winding '25 is thus energized for return of contact arm C to normal position, and as hereinbefore set forth the controlleris reset for a repeat work cycle by depression of push button l6.

What we claim as new and desire to secure by Letters Patent is:

1. In a machine tool controller, in combination, a first control switch operable to effect one operation of the machine, a second control switch operable to effect a different operation of the machine, a controllerbiased toward a given normal operating position and having a ratchet operating mechanism associated therewith for effecting step by step advance thereof out of normal position into a plurality of .other operatins positions, selector means associated with said controller for rendering one or the other of said control switches effective for operation of the machine in each of the operating positions of said controller, means for controlling said ratcheting mechanism to eifect an advance step of operation of said controller in response to either of the aforementioned operations of said machine and for permitting return of said controller to normal position upon completion of a selected sequence of operations of the machine, and means for rendering said selector means ineifective for control of said switches during return of said control device to normal position.

2. In a controller for effecting different operations of a machine tool in a preselected sequence, in combination, a plurality of selector switches and a control switch operable in a step by step manner out of a given normal position to successively establish circuit to said selector switches to render the same effective for control of the machine tool, said selector switches each having an off position and being settable in difierent positions for different operations of the machine, and means for efiecting an advance step of operation of said control switch in response to each operation of the machine.

3. In a controller for effecting different operations of a machine tool in a preselected sequence, in combination, a plurality of selector switches and a control switch operable in a step by step manner out of a given normal position to successively establish circuit to said selector switches to render the same effective for control of the machine tool, said selector switches each having an off position and being settable in different operating positions for different operations of the machine and operating means for said controller for efiecting a step of operation thereof in response to each operation of the machine and for returning the same to normal position upon movement of the controller into a position to establish circuit to a selector switch set in ofi position.

4. In a controller for effecting different operations of a machine tool in a preselected sequence, in combination, a plurality of selector switches and a control switch operable in a step by step manner out of a normal position to successively establish circuit to said selector switches to render the same efiective for control of the machine tool, said selector switches each having for returning the same to normal position upon movement of said controller into a position to establish circuit to a selector switch set in off position, and means for rendering said selector switches ineffective during return of said controller to normal position.

' 5. Ina grinding machine controller, in combination, a plurality of selector switches and a control switch operable in a step by step manner out of a given normal position to successively establish circuit to said selector switches to render the same eiiective for control of the machine, said selector switches each having an off position and being settable in one operating position for a grinding operation of the machine and in another operating position for a truing operation thereof, and said control switch having operating means associated therewith for effecting a step of operation thereof prior to completion of either a grinding or a truing operation of the machine.

6. In a grinding machine tool controller, in combination, a plurality of selector switches and a control switch operable in a step by step manner out of a given normal position to successively establish circuit to said selector switches to render the same effective for control of the machine, said selector switches having an off position and being movable into one operative position for a grinding operation of the machine and into another operative position for a truing operation thereof, and means for effecting a step of operation of said control switch away from normal position in response to either a grinding or a truing operation of the machine and for returning said control switch to normal position upon operation thereof into a position wherein the same establishes circuit to a selector switch set in off position.

7. In a grinding machine tool controller, in combination, a plurality of selector switches and a control switch operable in a step by step manner out of a given normal position to successively establish circuit to said selector switches 'to render the same effective for control of the machine, said selector switches having an off position and being movable into one operative position for a grinding operation of the machine and into another operative position for a truing operation thereof, and means for efiecting a step of operation of said control switch away from normal position in response to either a grinding or a truing operation of the machine and for returningfsaid control switch to normal position upon operation thereof into a position wherein the same establishes circuit to a selector switch set in off position, and means for rendering said selector switches ineffective for control of the machine during return of said control switch to normal position.

WALTER E. ADDICKS. ROBERT O. PERRINE,

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,684,486 Guild et al. Sept. is, 1928 2,192,308 Greiner et a1 Mar. 5, 1940 2,292,875 Flanders Aug. 11, 1942 2,317,226 Seyferth Apr. 20,-1943 

